The use of anonymous functions in php

1. Use as a callback function

<?php
echo preg_replace_callback('~-([a-z])~', function ($match) {
    return strtoupper($match[1]);
}, 'hello-world');
// 输出 helloWorld

2, as a variable assignment

<?php
$greet = function($name)
{
    printf("Hello %s\r\n", $name);
};

$greet('World');
$greet('PHP');

Result:

3. Inherit variables from parent scope

<?php
$message = 'hello';

// 没有 "use"
$example = function () {
    var_dump($message);
};
echo $example();

// 继承 $message
$example = function () use ($message) {
    var_dump($message);
};
echo $example();

result: